We have to consider some aspects like:
The overall aim.
An interesting and motivating topic.
Learning outcomes.
Activities and materials at the right level of learners.
Enough time for the set of activities.
Stages help to reach the main aim.
Stages developed logically.
An interesting starting point and an appropriate end of a lesson.
State personal aims if it necessary.
All of these will help us to ensure that our lesson is motivating and coherent at the correct level.
Reference:
Spratt, M., Pulverness, A., & Williams, M. (2012). The TKT Course Modules 1,2 and 3 (2nd ed.). New York: Cambridge University Press.